It's been more than a century since a Russian surgeon first described the simple and precise way to measure blood pressure that is still in use. We've learned a lot since then about what influences blood pressure and about how high blood pressure can wreak havoc throughout the body. What we haven't managed to do is get the public, and a fair number of doctors, to take high blood pressure seriously. Nearly two-thirds of the 65 million American adults with high blood pressure don't have it under control. That's a big problem, because it's a major cause of stroke, heart attack, heart and kidney failure, and early death.
In this special feature, we take a look at the latest thinking on this topic and offer 10 steps for getting your blood pressure under control and keeping it there.
Blood Pressure Basics
Some pressure is absolutely essential for circulation. Without it, blood couldn't move from the heart to the brain and toes and back again. The heart provides the driving force -- each contraction of the left ventricle, the heart's main pumping chamber, creates a wave of pressure that passes through the aorta and all the arteries in the body.
Relaxed and flexible arteries offer a healthy amount of resistance to each pulse of blood. Arteries that are tensed, constricted or rigid offer more resistance, which shows up as higher blood pressure. It also makes the heart work harder.High blood pressure is not a disease. Instead, it is a sign that something isn't right in the heart, blood vessels, kidneys or elsewhere. Sometimes it stems from the overproduction of hormones by the thyroid or adrenal glands. It can also be caused by the use of prescription or over-the-counter medications such as aspirin, ibuprofen, pseudoephedrine, some antidepressants, steroids and others. Most of the time, though, high blood pressure can't be traced to a specific source.
Doctors use the term hypertension. We'll stick with the more descriptive high blood pressure. Both mean the same thing.Measuring Change Blood pressure changes constantly. It responds instantly to what you are doing, thinking and feeling. It also follows a daily cycle, hitting a low point just before waking and peaking during midday. The reading taken in your doctor's office is merely a snapshot. All too often it's a shadowy, out-of-focus snapshot. Many doctors, nurses and medical assistants get incorrect readings because they don't follow the proper procedures for measuring blood pressure. What's more, some people have higher blood pressure in the doctor's office than at home, a discrepancy known as white-coat hypertension. Checking your blood pressure at home gives you and your doctor a much more accurate idea of your real blood pressure.No matter where your blood pressure is measured, these steps should be followed each time: Avoid tobacco and caffeine for at least 30 minutes before the test. Sit quietly for five minutes before the test. During the measurement, sit in a chair with your feet on the floor; your arm should be supported so your elbow is at about heart level. The inflatable part of the cuff should be placed on bare skin, not over a shirt, and should encircle at least 80 percent of your arm. Measure blood pressure twice, with a brief break in between.A standard blood pressure reading generates two numbers, as in 128/78. Each number represents millimeters of mercury (mm Hg), because the traditional measuring device used a glass column filled with mercury. The top number is the systolic pressure; the bottom number, the diastolic pressure.
Systolic pressure reflects the amount of pressure generated during systole (SIS-tuh-lee), the heart's pumping phase. It shows how hard the heart is working to push blood through the arteries. Diastolic pressure is the pressure during diastole (die-AS-tuh-lee), when the heart refills with blood between beats. It reflects how forcefully the arteries are being stretched most of the time.Alternative ways to gauge the state of the heart and blood vessels are gaining ground. One is pulse pressure, which is calculated by subtracting diastolic pressure from systolic pressure. The bigger the difference, the stiffer the arteries. Devices that measure the time it takes for a pulse wave to travel through the arterial system or that analyze the shape and frequency of blood pressure waves are also being used to judge the stiffness of arteries. Another approach, called impedance cardiography, tracks what happens to small electrical signals sent through the chest and blood vessels. This can assess the heart's ability to deliver blood to the body, the force the heart must pump against, and the amount of fluid in the chest.What's Normal? The definitions of normal and high blood pressure have been evolving over the years. Well into the 1970s, doctors didn't worry until systolic blood pressure topped 160 or diastolic jutted above 95. Since then, the cutoff between normal -- meaning healthy -- and high has been steadily falling.
The latest national guidelines (JNC-7) that doctors use to diagnose and treat high blood pressure set out four categories: normal (under 120/80), prehypertension (systolic 12 to 139 or diastolic 80 to 89), stage 1 hypertension (systolic 140 to 159 or diastolic 90 to 99), and stage 2 hypertension (systolic 160 or higher or diastolic 100 or higher). Each comes with recommendations on what should be done to decrease or control blood pressure, starting with lifestyle changes in prehypertension and moving on to medications and other therapies.The American Society of Hypertension (ASH) believes that there's more to the diagnosis than the numerical reading. A panel of ASH experts has proposed that early warnings of trouble in the heart, blood vessels, kidneys, or other target organs, or signs of damage in them, should be given as much emphasis as the blood pressure level itself. The group's approach makes sense -- it's a bit misleading to say that someone with a blood pressure of 119/79 is OK, while someone whose blood pressure is 121/81 has prehypertension.Looking at an individual's overall risk, instead of relying on a single number like blood pressure, means more work for doctors. But it would also lead to more aggressive efforts to identify and treat the people who need the most attention -- those with diabetes, kidney disease, or other signs of damage connected with high blood pressure.Next: 10 steps to better blood pressure >
Source: Health & Wellness